Code Check Objects: Main Considerations

Validating the integrity of a structural member involves assessing a range of durability and strength parameters. In the AEC|BOLT Building Design Suite, this process is facilitated through what we refer to as "Code Check Objects". (See also AEC|BOLT BIM Cloud Library [BDS]).

In this section, we aim to outline the general assumptions for one of the structural design templates provided by AEC|BOLT Design Templates within the AEC|BOLT Building Design Suite.

Primarily, the Code Check Objects are internally categorized into four main groups for validation:

i) Basic Compatibility Checks
ii) Compatibility Checks
iii) Axial and Flexural Checks
iv) Shear and Torsion Checks

i) Basic Compatibility Checks:

The Basic Compatibility Checks encompass fundamental criteria that must be met by a structural member to fulfill the required function and achieve the desired structural performance. If any of these checks are not satisfied during the initial design verification process, the AEC|BOLT Building Design Suite will halt further design procedures for the respective structural member until all checks are successfully fulfilled by the user.

Here are a few examples of the Basic Compatibility Checks based on ACI 318-14:

1. Adequate member dimensions and proportions.

2. Sufficient cover requirements for reinforcement.

3. Proper clear spacing between reinforcing bars.

4. Adequate concrete strength and quality.

5. Appropriate reinforcement detailing based on design considerations.

Example: Limits for concrete compressive strength (f’c) from Table 19.2.1.1

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Example: Minimum tie diameter allowed in Section 25.7.2.2

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To meet the design criteria mentioned earlier, the AEC|BOLT Building Design Suite performs checks on the user-defined concrete compressive strength and tie diameter before proceeding with further design verification.

In essence, the Basic Compatibility Checks prevent the design check from proceeding with potentially "erroneous" user inputs, ensuring that the design process is based on accurate and valid information.

ii) Compatibility Checks:

Before evaluating a member's response to force actions and deformations, Compatibility Checks serve as the complementary aspect to strength and serviceability design. If either of these checks is not satisfied by the user, the design iteration continues with strength checks, specifically iii) Axial and Flexural Checks, and iv) Shear and Torsion Checks.

Example: Minimum clear spacing of longitudinal reinforcement in members specified in Section 25.2.3

Example: Minimum and maximum longitudinal reinforcement for members satisfied in Section 10.6.1.1.

Unlike Basic Compatibility Checks, Compatibility Checks are typically fulfilled in conjunction with strength and serviceability design checks. Furthermore, Compatibility Checks define the minimum requirements that need to be satisfied, irrespective of force demands.

iii) Axial and Flexural Checks:

The Axial and Flexural Checks form a crucial part of the strength and serviceability assessments. These checks evaluate the section capacity and ensure geometric compatibility with the force actions involved. The section capacity can be categorized as:

1. Pure axial strength

2. Pure flexural strength

3. Combined axial and flexural strength

These checks are essential to verify the structural integrity and adequacy of the member under the given force actions.

Example: Maximum axial strength specified in Table 22.4.2.1

For cases that involve a combination of axial and flexural forces, the AEC|BOLT Building Design Suite incorporates a specially developed M-N interaction diagram. This diagram is included in the design report to provide a comprehensive visualization of the interaction between moment (M) and axial force (N) for the specific structural member. It helps engineers assess the behavior and capacity of the member under combined axial and flexural loading conditions

Example: Column slenderness effects defined in Section 6.2.6

An additional example discussed previously is the geometric compatibility check (slenderness) for axially loaded members, which is combined with an axial force capacity check. This particular check falls under the category of both strength and serviceability checks, rather than being solely a compatibility check. This is because the check considers both the geometric compatibility based on slenderness and the actual axial load results obtained from the structural analysis, which are treated as the demand. Thus, it encompasses aspects of both strength and serviceability to ensure the member's performance and integrity.

iv) Shear and Torsion Checks:

Another integral component of the strength and serviceability checks is the Shear and Torsion Checks. This set of checks evaluates the section capacity in terms of shear and torsional stresses. It ensures that the structural member can withstand and safely resist shear and torsional forces, thereby guaranteeing its structural integrity and performance.

Example: One-way shear strength - limitation for shear force demand in Section 22.5.1.2

Example: Cross sectional limits defined in Section 22.7.7 for a torsion-critical section

The two above cases further illustrate that the limitations and requirements for the section geometry are dependent on the force demands. This implies that both geometric compatibility checks and shear/torsional force/stress capacity checks are involved. These checks ensure that the section geometry is compatible with the force demands and that the member has the necessary capacity to resist shear and torsional forces and stresses.